Self-consistent problem of the excitation of beams of magnetostatic waves

An analytical solution is obtained for the self-consistent problem of the excitation of beams of magnetostatic waves by a converter of arbitrary type. Radiation patterns are calculated numerically for stripline converters at the frequencies where magnetostatic surface waves exist. Zh. Tekh. Fiz. 68, 95–101 (August 1998)     

Mid-IR Cathodoluminescence of Fe:ZnSe

Optics and Spectroscopy - The dependences of the integral intensity and kinetics of mid-IR cathodoluminescence (CL) of Fe:ZnSe crystals on an iron concentration varying from 0.01 to 14 wt % are...     

Bound-exciton emission bands in ZnSe single crystals and mixed plasmon-phonon modes

The paper reports a cathodoluminescence study of ZnSe single crystals annealed in a Bi melt at 1200 K for 120 h. It is found that the distance between the phonon structure satellites in the bound-exciton series I ₁ ^s -nLO and I ₁ ^d -nLO and the relative satellite intensity are different in samples with different conduction electron concentrations. It is shown that this difference is due to the mixing of the plasmon and phonon modes. The shape of the bound-exciton emission spectrum in ZnSe crystals in the 450–470 nm region is calculated, and a satisfactory agreement with the experiment calculations is obtained.     

Cathodoluminescence of ZnSe(Bi):Al crystals

The cathodoluminescence (CL) in ZnSe crystals annealed at T=1200 K in a Bi melt containing an aluminum impurity is investigated. The spectra are recorded for different excitation levels, temperatures, and detection delay times t ₀. As t ₀ is increased, the intensity of the orange band at λ _max=630 nm (1.968 eV) in the CL spectrum decreases in comparison to the intensity of the dominant yellow-green band at λ _max=550 nm (2.254 eV), whose half-width increases in the temperature range 6–120 K and then decreases as the temperature increases further. It is shown that such behavior of the yellow-green band is caused by the competition between two processes: recombination of donor-acceptor pairs and of free electrons with holes trapped on acceptors. The former mechanism is dominant at low temperatures, and the latter mechanism is dominant at high temperatures. At T∼120 mK the contributions of the two mechanisms to the luminescence are comparable. The resultant structureless band then achieves its greatest half-width, which is dictated by the interaction of the recombining charge carriers with longitudinal-optical and longitudinal-acoustic phonons and with the free-electron plasma. The mean number of longitudinal-optical phonons emitted per photon is determined mainly by their interaction with holes trapped on deep acceptors in the form of Al atoms replacing Se. The donor in the pair under consideration is an interstitial Al atom. Fiz. Tverd. Tela (St. Petersburg) 39, 1526–1531 (September 1997)     

The Influence of Annealing in Zinc Vapor on the Visible and Mid-IR Luminescence of ZnSe:Fe2+

Optics and Spectroscopy - The influence of annealing in zinc vapor on the impurity-defect composition and the IR cathodoluminescence (CL) of ZnSe:Te plates diffusion-doped with iron is studied....     

A new bound-exciton emission band in ZnSe crystals and multiplasmon optical transitions

We have investigated cathodoluminescence both in unannealed ZnSe crystals and in crystals annealed in a Bi melt at a temperature of 1200K for 120 h with subsequent quenching. In the wavelength range 450–480 nm we have detected a new line series I _i ^s -nLO-mPl consisting of the bound-exciton emission line I _i ^s with wavelength λ=455.9 nm and its plasmon and LO-phonon echoes I _i ^s -LO (λ ₁=461.3 nm), I _i ^s -2LO (λ ₂=466.8 nm), I _i ^s -3LO (λ ₃=472.4 nm), and I _i ^s -4LO (λ ₄=478.3 nm). We have determined the mean number of emitted LO phonons N _LO=2.2±0.1 per photon. It is shown that the observed finer structure of the band may be due to multiphonon optical transitions. At low plasma densities (ω _p ≪ω _LO ) the Coulomb interaction causes broadening of the I _i ^s -nLO series. In samples with denser plasma, in which the condition ω _p ⩽ω _LO is met, multiplasmon satellites of the series I _i ^s -nLO-mPl are observed. Theoretical calculations of the shape of the emission band agree with experiment. Fiz. Tverd. Tela (St. Petersburg) 41, 1176–1180 (July 1999)     

Influence of Annealing in Zinc Vapor on the Microstructure and Activator Radiation of ZnSe : Fe

Crystallography Reports - The effect of thermal treatment in zinc vapor on the stoichiometry, defect and impurity structure, and activator cathodoluminescence of ZnSe doped with iron by the thermal...